Many commercially available products such as leaf blowers, blenders, fans etc. use small motors having an impeller or propeller mounted to a rotor. Vibration in such devices can be unpleasant, and in some cases, cause injury to the operator or damage to the device itself when excessive. The vibration in such devices arises principally from rotational imbalance in the impeller or propeller assembly. For example, as the rotating assembly revolves at 15,000 rpm, any imbalance above about 0.6 gram inches causes unpleasant vibration.